Study: No differences in oncologic outcomes after RP among Hispanic vs non-Hispanic White men

A new study investigating ethnic disparities in prostate cancer cases found no evidence that Hispanic White men had worse outcomes after undergoing radical prostatectomy (RP) compared to non-Hispanic White men.¹ However, because of the limitations of the research, the findings need to be considered with caution, said Lourdes Guerrios-Rivera, MD, MSc.

“Our study was conducted utilizing the Shared Equal Access Regional Cancer Hospital (SEARCH), a robust multicenter and multiethnic database derived from the VA health system that was chosen to minimize potential confounding from differences in access to care. Besides, we focused on men with early-stage disease treated aggressively to minimize differences in practice patterns,” said Guerrios-Rivera, assistant professor of surgery, University of Puerto Rico School of Medicine, and urology staff, VA Caribbean Healthcare System, San Juan.

“However, SEARCH lacks granular data on country of origin, and that is a key limitation of our study because Hispanic individuals comprise a highly diverse population with subgroups in the United States differing culturally, socially, and possibly genetically. Therefore, it is important to state that our findings may not apply to all Hispanic subgroups and may miss important differences.”

Guerrios-Rivera is lead author of an article reporting the research. After excluding men who received neoadjuvant treatment, as well as those missing information on baseline disease-related characteristics and follow-up, it analyzed data from 3789 White men who underwent RP between 1988 and 2017. Of the included population, 236 (6%) were Hispanic.

Baseline disease-related characteristics between the Hispanic and non-Hispanic White men were similar except mean prostate-specific antigen (PSA), which was higher in the Hispanic group. Multivariable analysis adjusting for age, PSA, clinical stage, biopsy grade group, surgery year, and surgical center found no ethnicity-related differences in pathological features, including extracapsular extension, seminal vesicle invasion, positive margins, positive lymph nodes, or high-grade disease.

During a median follow-up of 7.9 years, biochemical recurrence occurred in 1168 men, 182 men developed metastasis, and 132 men developed castration-resistant prostate cancer. Findings from multivariable analysis showed that none of the oncologic outcomes were significantly associated with Hispanic ethnicity.

“In fact, the results for all 3 outcomes showed a numerical difference favoring the Hispanic men. However, none of the differences achieved statistical significance,” Guerrios-Rivera said.

In addition to the inability to subgroup Hispanic men by country of origin, the study’s focus on men undergoing RP is another issue that limits the generalization of its findings.

“Treatment selection differences may exist among White Hispanic men, because race may influence the patient’s opinion for treatment selection,” Guerrios-Rivera said.

“Further studies are needed to investigate ethnicity-related differences in outcomes after other treatments for prostate cancer.”

There have been relatively few studies investigating associations between Hispanic ethnicity and outcomes after definitive treatment for prostate cancer, but the available research has generated conflicting results. Two small, single-institution studies of men undergoing RP found no differences among Hispanic men.^2,3 However, results of a more recent population-based study showed higher rates of prostate cancer-specific mortality after RP for Puerto Rican men than for both non-Hispanic White men and non-Hispanic Black men.⁴

“The latter findings are interesting in that in Puerto Rico, most men labeled as Hispanic White have some African ancestry due to extensive genetic admixture. As such, whether the findings of worse outcomes among men from Puerto Rico is due to African ancestry, which is known to impact poor outcomes, a unique mix of genetics, or environmental factors specific to Puerto Rico is not known,” Guerrios-Rivera said.

Overall, the available evidence indicates that a better understanding of the diversity within the Hispanic population may shed important light on health disparities and prostate cancer biology.

“It is our interest to develop future studies addressing prostate cancer disparities, particularly in Puerto Rican men, by evaluating the genomic and the immune biologic signatures of those populations at risk of progression,” Guerrios-Rivera told Urology Times®.

References

1. Guerrios-Rivera L, Howard LE, Klaassen Z, et al. Do Hispanic men have worse outcomes after radical prostatectomy? Results from SEARCH. Urology. Published online November 12, 2020. doi:10.1016/j.urology.2020.10.043

2. Lam JS, Sclar JD, Desai M, Mansukhani MM, Benson MC, Goluboff ET. Is Hispanic race an important predictor of treatment failure following radical prostatectomy for prostate cancer?
J Urol. 2004;172(5)(suppl 1):1856-1859. doi:10.1097/01.ju.0000141783.67470.55

3. Gomez P, Manoharan M, Sved P, Kim SS, Soloway MS. Radical retropubic prostatectomy in Hispanic patients. Cancer. 2004;100(8):1628-1632. doi:10.1002/cncr.20127

4. Velasquez MC, Chinea FM, Kwon D, et al. The influence of ethnic heterogeneity on prostate cancer mortality after radical prostatectomy in Hispanic or Latino men: a population-based analysis. Urology. 2018;117:108-114. doi:10.1016/j.urology.2018.03.036